Water heater



B. L. ELAM WATER HEATER Feb. 23, 1937.

Filed Aug. 19, 1956 Bernard/[1.

Patented Feb. 23, 1937 UNITED STATES PATENT OFFICE WATER HEATER Virginia Application August 19, 1936, Serial No. 96,880

6 Claims.

This invention relates to a water heater of the type in which the water itself disposed between two or more spaced electrodes forms the resistance.

Such heaters have not been satisfactory for a number of reasons not among the least of which resides in the fact that they are inedicient and consume more current than is necessary to bring the water to boiling. This will be apparent from the tables referred to hereinafter. The present invention is designed to overcome this and other disadvantages present in the known arrangements and this is the major object of the invention.

The invention has for another object the provision of a water heater of the general type in question which is automatically controlled so as to consume only the least amount of current to obtain the most eflicient heating.

Another object of the invention is to provide a water heater which as a unit can easily be installed in a domestic water boiler.

It has been established that there is a definite relationship between the current consumption in terms of amperes and the temperature of the water. Still another object of the invention is the provision of a water heater which is de signed to capitalize to the greatest extent on such relationship.

As another object the invention is designed to place on the market a water heater of great simplicity in construction which still combines the adjustable feature.

These and other objects of the invention will become more apparent from the following description when read in conjunction with the accompanying drawing in which:

Fig. 1 is a side elevation partially in section of a heater unit made in accordance with the invention.

Fig. 2 is a partial end view of the arrangement shown in Fig. 1.

Fig. 3 is a plan view of the arrangement.

The invention will be illustrated and described as embodied in a water heater for use in heating a domestic water supply. In such instances a boiler supply tank is usually provided in the kitchen or basement and is connected by suitable arrangement so that the heater unit will begin to operate as soon as any hot water faucet in the dwelling is turned on. These boilers are also heated from burners which must be lighted manually when it is desired to heat water.

The heater unit shown in the drawing is designed to be secured preferably in a lower wall of such boiler tanks or in the bottom thereof so that the electrodes extend inwardly into the tank several inches. This may be accomplished by mounting the electrodes on a base plate 2 of metal or other suitable material and by securing this plate to the wall of the boiler tank. If the boiler wall is round the base plate 2 must, of course, be correspondingly curved.

Mounted in the base plate 2 so as to be insulated therefrom if the base plate is of conducting metal are three electrode posts 4, 6 and 8 the cuter ends of each being adapted to be connected with the lines of a source of electric energy. The electrode posts are preferably of brass but may be of other suitable conducting metal. The arrangement shown is adapted for three phase alternating current and the electrode posts are connected to positive, negative and ground. While a single phase alternating current and even direct current may be used with the invention in some of its embodiments and adaptations, the three phase alternating' current has been found to be best for various reasons and, moreover, the connection in rotation to positive, negative and ground insures against the possibility of current leakage from the electricity passing between the electrodes.

A very satisfactory method of insulating the brass electrode posts 4, 6 and 8 from the base plate 2 is illustrated at the lower left corner of Fig. 1. Two insulating members I0 and I2 of suitable material such as bakelite are provided with vertical bores for the passage of an electrode post. The inner end of the members I0 and I2 are of reduced diameter and are designed to form a telescoping connection. The members are held rigidly in closed telescoping position and so that the shoulders I4 and I6 abut tightly against the surfaces of the plate by means of nuts I8 and 20 threaded on the electrode posts.

Extending upwardly from the center brass electrode post 6 and rigidly secured thereto is a support 22 preferably of a conducting metal. The support shown is a bifurcated support between the upper ends of which is secured a carbon electrode plate 24. The plate 24 is provid-ed with a central aperture in which the enlarged central portion 26 of the axle 28 is snugly fitted. The axle 28 may be of any suitable rigid insulating material such as bakelite.

The reference numbers 30 and 32 indicate spac er elements of suitable insulating material which elements are disposed on the axle 28 as are the movable carbon plates 34 and 36. The spacer elements and 32 prevent the carbon plates Se and 3@ from ever coming closer than a predetermined distance irc-m the stationary carbon plate 24.

Mounted on the outer sides of the carbon plates 3i! and 32 and so that the cores therein will be in alignment with the openings in the carbon plates are sleeve members 3S and of conducting metal or mate 1ial. It will be noted that the sleeves possess flanges 42 and it respectively so as to provide suitable surfaces to permit the sleeves to be secured rigidly to the carbon plates 34 and The sleeves 38 and have a slidable it on the ends of the axle 28. The outer ends of the sleeves are internally screw threaded to receive screws it and i8 by means of which the sleeves and consequently the carbon plates 3 and 36 respectively are secured to U-shaped bi-metallic elements and The biemetallic U-shaped elements are in turn secured rigidly to uprights 54 and 5G of conduct ing material extending upwardly from the electrode posts il and 8 respectively. The metal strips comprising the bi-metallic elements have dil"- erent coefficients of expansion.

While the operation or the device should be apparent from the above, it will be mentioned briefly. It has been stated that the brass posts 4, E and t are connected in a three phas-e alternating current. The whole unit is disposed in the wall of a water supply tank so that the 1ci-metallic elements and the carbon. plates 2li, 34 and 36 extend inwardly into the water. When the oure rent is switched on, either manually or through some arrangement operating upon opening a hot water faucet, the current will pass up through the electrode posts, upright supports, and bi-metallic elements to the carbon plates. Since water used for domestic supply is not chemically pure it will offer resistance to the passage of the current from one plate to another and consequently will become heated. As the water heats the bi-metallic elements will be affected by the increasing heat and will operate to pull the two outer carbon plates and farther away from the stationary center carbon plate 2li. The two outer carbon plates during this pulling movement slide outwardly simultaneously on the axle 2S and in so doing are guided and steadied by the sleeves 3B and if cold water is supplied to the tank and the temperature of the water is materially lowered the 1tri-metallic elements will be aiected so as to push the outer carbon plates inwardly. This pushing movement is, however, limited by the spacer elements 35i and 32. t has been found that spacer elements of about one-eighth of an provide satisfactory inner limits for the carbon plates although this may vary under certain circumstances and conditions.

Because of the simple construction of the arrangement and the automatic control of the carbon plates in accordance with the temperature of the water, the water can be brought to boiling in a very short time with a much less expenditure of current than would otherwise be necessary. It is round that sometimes the iluctuation of current is as high as 126% in known arrangeand the current consumption is often so high as to be objected to by the agency furnishing the electricity. rlhe internal control provided by invention overcomes this great fluctuation and expenditure of current.

it is frequently as important to step up the consumption as to lower it as, for example, when very cold water is fed to the boiler or storage tank. The present arrangement can be adjusted originally so that the plates may be moved closer together to care for such a contingency.

The importance of an adjustable unit made in accordance with the teachings of the invention can be grasped to some extent from the following results of a test conducted recently. This test involved a comparison between an arrangement having stationary plates and an arrangement such as described and illustrated herein.

The heater units were placed in 21/2 gallon open glass containers filled with water. 220 volt alternating current with a three phase connection was employed. With the non-adjustable arrangement the results were as follows:

- Current in Minutes ampems Temperature F. 0 8. 4 76 i 8.8 2 9.6 112 3 10. 6 129 4 11.2 148 5 12. 2 168 6 13. 6 190 7 14. 4 204 8 15.6 212 9 16. 6 212 l0 14. 6 212 11 14.8 212 l2 14.4 212 13 14. 212

Percam* Beginning aniperage.. 8. 4 =100 Low ampcrage,

minute 8.4 High amperage, 9th

minute... 16. 6 :195 Average ampersgc 12. 84:153

The results with the arrangement made in accordance with the present invention were as follows:

Currcnt in r amperes Tempcratu e Minutos Beginning amperage Low` ampcrage, 13th trated and described may be made without departing from the spirit of the invention. For example, water in various localities will differ radically in composition depending on the kind and quantity of impurities therein. Because of such impurities the water may offer more or less resistance to electricity. In some instances it may be found to be more suitable to use more carbon plates or to increase the size and shape of these plates. The number and size of the plates will also be dictated in a measure by the heating requirements.

Moreover, while the invention has been illustrated and described as a unit for use in domestic Water boilers, other uses readily suggest themselves. For example, the invention may be employed to heat dwellings by being disposed in a furnace boiler or individual radiators may be equipped with units. Small units may be used in sterilizing equipment for doctors and dentists. Such uses being manifold I do not intend to be limited to the exact construction illustrated and described except as indicated in the claims which follow.

Having described my invention, what I claim as new and desire to protect by Letters Patent of the United States is:

1. In an electric water heating apparatus of the type in which the water itself serves as the resistance, a stationary carbon plate electrode, a pair of movable carbon plate electrodes disposed one on each side of said stationary plate electrode, means for moving said pair of plate electrodes toward and away from said stationary plate in accordance with the temperature of the water as it is heated, heating of the water causing movement of said pair of plate electrodes away from said stationary plate electrode, said means comprising U-shaped bi-metallic elements the metals of which have different coefficients of expansion, one portion of said bi-metallic elements being connected to the outer surfaces of said movable plate electrodes, the other portion being connected to a stationary member, and means to guide the movement of said pair of plate electrodes, said last named means comprising an axle passing through centrally disposed apertures in said plate electrodes, said axle having a stationary connection with said stationary plate electrode and a sliding connection with said other plate electrodes, and means for connecting said plate electrodes to a source of three phase alternating current.

2. In an electric water heating apparatus of the type in which the water itself serves as the resistance, a stationary plate electrode, at least one movable plate electrode disposed on one side of said stationary plate electrode, mechanism responsive to changes in temperature for moving said movable plate electrode toward and away from said stationary plate electrode in accordance with the temperature of the water as it is heated, heating of the water causing movement of said movable plate electrode away from said stationary plate electrode, said mechanism having one portion connected to the outer surface o f said movable plate electrode and another portion connected to a stationary member, and means to guide the movement of said movable plate electrode, said last mentioned means comprising an axle passing through a centrally disposed aperture in said movable plate electrode and having a rigid connection with said stationary plate electrode and a sliding connection with said movable plate electrode, means for connecting said plate electrodes to a source of current.

3. In an electric water heating apparatus of the type in which the water itself serves as the resistance, a stationary plate electrode, at least one movable plate electrode disposed on one side of said stationary plate electrode, mechanism responsive to changes in temperature for moving said movable plate electrode toward and away from said stationary plate electrode in accordance with the temperature of the water as it is heated, heating of the water causing movement ofY said movable plate electrode away from said stationary plate electrode, said mechanism comprising a by-metallic element, the metals of which have different coeiiicients of expansion, one portion of said by-metallic element being connected to the outer surface of said movable plate electrode, the other portion being connected to a stationary member, and means to guide the movement of said movable plate electrode, said.

last named means comprising an axle passing through a centrally disposed aperture in said movable plate electrode, and having a rigid connection with said stationary plate electrode and a sliding connection with said movable plate electrode, and means for connecting said plate electrodes to a source of current.

4. In an electric water heating apparatus of the type in which the water itself serves as the resistance, a stationary plate electrode, at least one movable plate electrode disposed on one side of said stationary plate electrode, mechanism responsive to changes in temperature for moving said movable plate electrode toward and away from said stationary electrode in accordance withthe temperature of the water as it is heated, heating of the water causing movement of said movable plate electrode away from said stationary plate electrode, said mechanism having one portion connected to the outer surface of said movable plate electrode, the other portion being connected to a stationary member, spacing means disposed between said plate electrodes, and means to guide the movement of said movable electrode so that the adjacent surfaces of said electrodes are made parallel at all times, said last named means comprising an axle passing through centrally disposed apertures in said movable plate electrode and said spacing means and into an aligned aperture in said stationary plate electrode, said axle having a rigid connection with said stationary plate electrode and a sliding connection with said movable plate electrode, and means for connecting said movable plate electrodes to a source of current.

5. In an electric water heating apparatus of the type in which the water itself serves as the resistance, a stationary plate electrode having a centrally disposed aperture therein, a movable plate electrode disposed on one side of said stationary plate electrode and having a centrally disposed aperture adapted to align with the aperture in said stationary plate electrode, a spacing member disposed between said plate electrodes and having a centrally disposed aperture adapted to align with said other mentioned apertures, said movable plate electrode having a projecting sleeve rigidly secured thereto and extending laterally therefrom, the bore of said sleeve being in alignment with the aperture in said movable plate electrode, mechanism responsive to changes in temperature for moving said movable plate electrode toward and away from said stationary plate electrode in accordance with the temperature of the water as it is heated, heating o1 the water causing movement of said movable plate electrode away from said stationary plate electrode, one portion of said mechanism being connected to the outer end of said sleeve and the other portion being connected to a stationary member, and means to guide the movement of said movable plate electrode, said last mentioned means comprising an axle passing through the apertures in said stationary plate electrode, said spacing member, said movable electrode and the sleeve rigidly connected therewith, said axle having a rigid connection with said stationary plate electrode and a sliding connection with said movable plate electrode and the rigidly connected sleeve, and means for connecting said plate electrodes to a source of current.

6. In an electric Water heating apparatus of the type in which the water itself serves as the resistance, a stationary plate electrode, at least one movable plate electrode disposed on one side of said stationary plate electrode, mechanism responsive to changes in temperature for moving said movable plate electrode toward and away from said stationary plate electrode in accordance with the temperature of the Water as it is heated, heating of the water causing movement o said movable plate electrode away from said stationary plate electrode, said mechanism having one portion connected to the outer surface of said movable plate electrode and another portion connected to a stationary member, and means to guide the movement of said movable plate electrode to keep the surfaces of the plate electrodes parallel at all times, said last mentioned means comprising an axle passing through a centrally disposed aperture in one of said plate electrodes and having a sliding connection therewith and having a rigid connection with said other plate electrode, and means for connecting said plate electrodes to a source of current.

BERNARD L. ELAM. 

